Study Compares Indicators of Fluid Overload in Patients on Hemodialysis

San Diego—In patients receiving hemodialysis therapy, fluid overload is associated with increased mortality and is often undiagnosed. Diagnosis of fluid overload determined via physical examination, including systolic and diastolic blood pressure, lung crackles (rales), lower extremity edema, jugular venous distention (JVC), n-terminal pro-B-type natriuretic peptide (BNP), and findings on chest x-ray or thoracic computed tomography (CT). In addition, point-of-care ultrasound is a powerful tool for determination of fluid overload using measurements of the inferior vena cava (IVC) and quantitative 28-point lung ultrasonography for B-line score (BLS).

Erik Yarmey, MD, and colleagues at the University of Pennsylvania, Philadelphia, conducted a cohort study designed to compare indicators of fluid overload in patients on hemodialysis. Study results were reported during a poster session at Kidney Week 2018 in a poster titled Comparison of Indicators of Fluid Overload in Hemodialysis Patients.

The study included patients (n=101) with end-stage renal disease on hemodialysis from a large urban emergency department at a referral center. Exclusion criteria included inability to consent. Fluid overload indicators were obtained prior to first hemodialysis, including BLS. Two independent observers graded IVC size and collapse on a four-point scale. Ten indicators of fluid overload (BLS, IVC, chest x-ray, CT, BNP, rales, lower extremity edema, JVD, and systolic and diastolic blood pressure) were compared with the presence or absence of fluid overload as determined by the treating nephrologist or on chart review

Median age of the cohort was 60 years, 51% were male, and 84% identified as black or African American. Comorbidities included diabetes (65%), coronary artery disease (27%), airways disease (33%), systolic heart failure (40%), and diastolic heart failure (75%). Median dialysis vintage was 33 months; 54% had arteriovenous fistula access, 29% had graft access, and 17% had catheter access. Residual kidney function was minimal overall. On arrival to the ED, 62% had fluid overload; 27% of the ED visits were for fluid overload.

BLS was available for the 101 patients; median BLS score was 34. The area under the receiver-operator characteristic curve (AUC) was 0.95 for BLS (95% confidence interval, 0.92-0.99) with optimal cutoff of 30. AUC for edema was 0.60 (95% CI, 0.53-0.68); for rales, 0.60 (95% CI, 0.54-0.66); for JVD, 0.53 (95% CI, 0.50-0.56); for systolic blood pressure, 0.53 (95% CI, 0.41-0.65); and for diastolic blood pressure, 0.49 (95% CI, 0.38-0.61). IVC was obtained for 37 patients (AUC, 0.78; 95% CI, 0.61-0.95); BNP was obtained on 39 patients (AUC, 0.80; 95% CI, 0.63-0.98), chest x-ray on 76 patients (AUC, 0.71; 95%CI, 0.61-0.80), and CT on 20 patients (AUC, 0.91; 95% CI, 0.81-1.00).

In summary, the researchers said, “Quantitative BLS outperforms conventional physical exam, serologic, and other imaging indicators in determination of fluid overload in hemodialysis patients.”

Source: Yarmey E, Mazumder P, Brown J, et al. Comparison of indicators of fluid overload in hemodialysis patients. Abstract of a poster (FR-PO277) presented at the American Society of Nephrology Kidney Week 2018, October 26, 2018, San Diego, California.